1. Field of the Invention
The present invention relates to a small-sized portable information processing apparatus, such as a portable calculation machine, a portable computer, a word processor, an electronic notebook or the like and, more particularly, relates to a small-sized and light-weight portable information processing apparatus having a cooling means.
During the recent development of small-sized portable information processing apparatuses, it has been required that the devices should be easy to handle. On the other hand, upon developments of high-speed electronic elements, such CPUs or the like, and a smaller sized information processing apparatus, it has been required that such an apparatus should effectively be cooled so that the heat from the CPU or the like be removed.
2. Description of the Related Art
A conventional type small-sized portable information processing apparatus comprises an apparatus body having an input section, i.e., a keyboard, and a lid section provided with a liquid crystal display which is pivotably attached to the apparatus body by means of a hinge, so that the liquid crystal display can be opened or closed with respect to the apparatus body. It is known that, in order to easily handle such an apparatus during an input operation, the keyboard may be inclined when the liquid crystal display is opened with respect to the apparatus body.
For example Unexamined Patent Publication (Kokai) No. 7-319579 (JPP'579) discloses that a keyboard cooperates with an apparatus body to automatically incline so that an input operation can easily performed when a display is pivotably opened with respect to the apparatus body by means of a hinge. Also, Unexamined Patent Publication (Kokai) No. 5-250091 (JPP'091) discloses that, after a lid section is opened to expose a keyboard and then the keyboard is inclined with respect to the apparatus body, a track ball is exposed so that the track ball can be handled.
On the other hand, upon development of high-speed electronic elements, such as CPU or the like, and a smaller sized information processing apparatus, it has been required that such an apparatus should be effectively cooled so that the heat generated by the CPU or the like during the operation thereof can be removed. In this connection, the following cooling means are known. For example, Unexamined Patent Publication (Kokai) No. 4-290107 (JPP'107) discloses that an apparatus body is provided with an air suction port at a wall thereof and an air outlet port at the back of a hinge to effectively cool the apparatus and prevent dust from entering into the inside thereof. Also, Unexamined Patent Publication (Kokai) Nos. 5-304379 (JPP'379) and 8-263162 (JPP'162) disclose that an apparatus body is provided with an air suction port at a wall thereof and a small-sized fan to forcibly remove the heat generated by the electronic elements in the apparatus.
In addition, Unexamined Patent Publication (Kokai) No. 9-34590 (JPP'590) discloses that, when a display is opened by means of a hinge with respect to an apparatus body, the keyboard is automatically inclined and simultaneously an air port is formed between the apparatus body and the keyboard, so that an input operation can easily performed and also a cooling effect of the apparatus can be improved.
However, the above-mentioned apparatuses known in the prior art have the following disadvantages. For example, as disclosed in JPP'579 and JPP'091, if a keyboard is inclined with respect to the apparatus body to a position in which an input operation can be easily performed, the cooling efficiency is not sufficient so that it is not suitable for a highly dense mounting, although the keyboard input operation can effectively be performed.
In addition, in the apparatus having a cooling air inlet port as disclosed in JPP'107, or the apparatus having a cooling fan as disclosed in JPP'379 and JPP'162, the keyboard is not inclined with respect to the apparatus body when the lid is opened and, therefore, an input operation cannot easily be performed, although the cooling efficiency is relatively good.
Also, a cooling fan gives rise to a problem of noise generation, a provision of a heat radiation plate or the like has a limit in the cooling efficiency, and provision of air port gives rise to a problem that the size of the air port is not sufficient to obtain a good cooling efficiency in view of the size reduction and various needs for the apparatus.
In JPP'590, during the operation state in which a display is opened, the keyboard is automatically inclined and simultaneously an air port is formed between the apparatus body and the keyboard. Therefore, the input operation can easily be performed and also a cooling effect of the apparatus can be improved.
However, in JPP'590, the keyboard is pivotably connected to the apparatus body by means of a slide hinge and thus the lid having a display and keyboard are directly connected to each other by means of hinge, the inclined angle of the display is changed in accordance with the angle of the display, which is not constant during the operation. Since there is no means for locking the keyboard at a constant angle, the inclined angle can be changed when an external force is exerted onto the keyboard during the input operation.